ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Recently, Mg-Zn-Y alloys with superior performance, which have a long period stackingorder (LPSO) phase, have been developed. Therefore, it is important to understand fundamentalfatigue properties in such materials. In this study, the fatigue fracture behavior of the Mg96Zn2Y2alloy has been investigated with a plain bending testing machine, which was originally developedfor thin sheet specimen at room temperature and 523K. One end of the sheet specimen is fixed at avoice coil of the loudspeaker and the other end is set free. A bending mode resonance occurs in thespecimen due to forced vibration at the fixed end. To estimate stress amplitude of bending,deflections at the free end of the specimen oscillating at a frequency of about 200~500Hz wasmeasured by a laser displacement gauge. For comparison, AZ31B alloy also has been investigated.S-N curve for the Mg96Zn2Y2 alloy was obtained using a stress ratio of R=-1, and the fatiguestrengths were estimated as 200MPa at room temperature and 120MPa at 523K at 106~107 cycles.These values correspond to about 50% of 0.2% proof strengths of the Mg96Zn2Y2 alloy. Two typesof fatigue surface were observed in the Mg96Zn2Y2 alloy. One was striation-like-pattern and theother was relatively flat surface. Striation-like-pattern was similar to fatigue surface of AZ31B.Therefore, these two types of fatigue surface correspond to crack passing through α-Mg phase andLPSO phase, respectively. The feature of fracture surface at 523K was almost the same as that atroom temperature
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/17/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.561-565.267.pdf
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